The Fall Furnace Checklist for Seattle-Area Homes

The first truly cold night in Seattle usually arrives in late October or November, and that is when our phones light up with furnaces that will not start. Most of those calls are preventable. Here is a checklist to run through before the heating season begins.

What you can do yourself

• Replace the filter. A clogged filter is the single most common cause of heating problems we see. Check it monthly during the season.
• Test the thermostat. Switch to heat, raise the setpoint a few degrees, and confirm the furnace starts and warm air arrives within a few minutes.
• Clear the area around the furnace. Keep at least three feet clear, and never store paint, solvents, or cardboard nearby.
• Check supply and return vents. Make sure furniture and rugs are not blocking airflow.
• Look at the exhaust vent outside. Confirm it is clear of leaves, nests, and debris.
• Test your carbon monoxide detectors and replace batteries.

What a professional tune-up covers

• Heat exchanger inspection for cracks, the most important safety check on any gas furnace
• Burner cleaning and flame inspection
• Igniter and flame sensor testing and cleaning
• Blower motor, wheel, and capacitor check
• Gas pressure and temperature-rise measurement
• Safety control and limit switch testing
• Condensate drain and trap cleaning on high-efficiency furnaces
• Carbon monoxide screening at the registers

Why the timing matters

Scheduling a tune-up in September or early October means you are ahead of the rush, and if the inspection finds something that needs repair, you have time to fix it on your schedule rather than during a cold snap. It also documents maintenance for your manufacturer warranty.

Signs you should not wait

If your furnace is making new noises, short cycling, producing a burning smell that does not clear within a few minutes of the first start, or if a CO detector has ever alarmed, stop using it and call for service. Those are not tune-up items; they are repair calls.